Detection of Pedestrian Using Radio Devices

ABSTRACT

The present radio system transmits an electromagnetic signal to nearby devices requesting the device respond. The radio system also receives responses to the electromagnetic signal from the nearby devices. Based on the radio technology used, the signaling of the transmitted electromagnetic signal may be varied. For example, the transmitted electromagnetic signal may be a Bluetooth, 802.11, or other radio signal. A device that received the signal from the radio unit may transmit a response signal with the same radio technology. However, in some instances, the radio technology used for communication may operate on several radio (e.g., frequency) channels. Both the transmitter and receiver must operate on the same channel at the same time in order to communicate. Thus, it may be desirable to transmit the electromagnetic signal on more than one channel at the same time, in order to increase the chances that a nearby device responds.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. patent application Ser.No. 16/456,561, filed Jun. 27, 2019, U.S. patent application Ser. No.15/154,366 (now U.S. Pat. No. 10,377,374), filed on May 13, 2016, andU.S. patent application Ser. No. 14/073,335, filed on Nov. 6, 2013, theentire contents of all are herein incorporated by reference.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

A vehicle could be any wheeled, powered vehicle and may include a car,truck, motorcycle, bus, etc. Vehicles can be utilized for various taskssuch as transportation of people and goods, as well as many other uses.

Some vehicles may be partially or fully autonomous. For instance, when avehicle is in an autonomous mode, some or all of the driving aspects ofvehicle operation can be handled by a vehicle control system. In suchcases, computing devices located onboard and/or in a server networkcould be operable to carry out functions such as planning a drivingroute, sensing aspects of the vehicle, sensing the environment of thevehicle, and controlling drive components such as steering, throttle,and brake. Thus, autonomous vehicles may reduce or eliminate the needfor human interaction in various aspects of vehicle operation.

SUMMARY

Many pedestrians carry wireless devices in their pockets. These wirelessdevices may be able to receive and transmit radio signals. Radio signalstransmitted by the wireless device may be communicated to either awireless base station (e.g., a cellular base station, 802.11 basestation, or other base station) or another wireless device. Anautonomous car and/or other types of autonomous vehicles may be able toreceive radio signals transmitted by wireless devices that are carriedby pedestrians. By detecting signals that are emitted by a pedestrian'smobile device, an autonomous car may be able to detect the location ofpedestrians. In some cases, the radio signals transmitted by thewireless device may be encoded in a way the vehicle is unable decode.However, the simple presence of such a radio signal may be sufficient tolocate a pedestrian in possession of the emitting device, even when theautonomous car is unable to decode the radio signal, . Further, in someembodiments, the vehicle may transmit signals in order to evoke aresponsive signal from the wireless device. For example, an autonomousvehicle could transmit a Bluetooth discovery signal to get a responsefrom wireless devices. Other examples are possible.

An apparatus disclosed herein includes a sensor unit. The sensor unitmay be configured to transmit a device-discovery radio signal. Thedevice-discovery radio signal may include a request for any nearbydevice to transmit a responsive radio signal. The device-discovery radiosignal may be transmitted on more than one channel of a radio spectrumassociated with the radio signal at the same time. The sensor unit maybe further configured to receive, in response to the device-discoveryradio signal, a responsive radio signal. The apparatus may also includea processing unit. The processing unit may be configured to analyze theresponsive radio signal to determine that the responsive radio signal isassociated with a pedestrian. The processing unit may be furtherconfigured to alter the control of the apparatus based on the presenceof the pedestrian based on the received radio signal being associatedwith a pedestrian.

Methods disclosed herein include transmitting a discovery radio signal,where the discovery radio signal will cause nearby devices to transmit aresponse radio signal. Additionally, the discovery radio signal may betransmitted on more than one channel of a radio spectrum associated withthe radio signal at the same time. The method also includes receiving aresponse radio signal and analyzing the response radio signal todetermine if the radio signal is associated with a pedestrian. Based onthe received radio signal being associated with a pedestrian, the methodmay alter the control of the apparatus by a control system based on thepresence of the pedestrian.

An article of manufacture including a non-transitory computer-readablemedium having stored thereon program instructions that, if executed by aprocessor in a radio system, cause the radio system to performoperations comprising transmitting a discovery radio signal, where thediscovery radio signal will cause nearby devices to transmit a responseradio signal. Additionally, the discovery radio signal may betransmitted on more than one channel of a radio spectrum associate withthe radio signal at the same time. The method also includes receiving aresponse radio signal and analyzing the response radio signal todetermine if the radio signal is associated with a pedestrian. Based onthe received radio signal being associated with a pedestrian, the methodmay alter the control of the apparatus by a control system based on thepresence of the pedestrian.

An apparatus disclosed herein includes a means for sensing. The meansfor sensing unit may be configured with a means for transmitting adevice-discovery radio signal. The device-discovery radio signal mayinclude a request for any nearby device to transmit a responsive radiosignal. The device-discovery radio signal may be transmitted by themeans for transmitting on more than one channel of a radio spectrumassociate with the radio signal at the same time. The means for sensingmay be further configured with a means for receiving, in response to thedevice-discovery radio signal, a responsive radio signal. The apparatusmay also include a means for processing. The means for processing may beconfigured to analyze the responsive radio signal to determine that theresponsive radio signal is associated with a pedestrian. The means forprocessing may be further configured to alter the control of theapparatus based on the presence of the pedestrian based on the receivedradio signal being associated with a pedestrian.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the figures and the followingdetailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram illustrating a vehicle, accordingto an example embodiment.

FIG. 2 shows a vehicle, according to an example embodiment.

FIG. 3 shows a method, according to an example embodiment.

FIG. 4A is a top view of an autonomous vehicle operating scenario,according to an example embodiment.

FIG. 4B is a top view of an autonomous vehicle operating scenario,according to an example embodiment.

FIG. 4C is a top view of an autonomous vehicle operating scenario,according to an example embodiment.

FIG. 5 is a schematic diagram of a computer program product, accordingto an example embodiment.

DETAILED DESCRIPTION

Example methods and systems are described herein. Any example embodimentor feature described herein is not necessarily to be construed aspreferred or advantageous over other embodiments or features. Theexample embodiments described herein are not meant to be limiting. Itwill be readily understood that certain aspects of the disclosed systemsand methods can be arranged and combined in a wide variety of differentconfigurations, all of which are contemplated herein.

Furthermore, the particular arrangements shown in the Figures should notbe viewed as limiting. It should be understood that other embodimentsmight include more or less of each element shown in a given Figure.Further, some of the illustrated elements may be combined or omitted.Yet further, an example embodiment may include elements that are notillustrated in the Figures.

Example embodiments disclosed herein relate to a radio system to detectpedestrians within the vicinity of an autonomous vehicle. Further, theembodiments disclosed herein may also be used to identify the locationof pedestrians based on the received radio signals.

The radio system of the autonomous vehicle may feature a plurality ofantennas. Each antenna may be configured to (i) transmit electromagneticsignals, (ii) receive electromagnetic signals, or (iii) both transmitand receive electromagnetic signals. The antennas may form an array ofantenna elements. In some examples, the array may be able to steer abeam formed by the transmitted electromagnetic signals. Additionally,the array may aid in detecting the angle and range from whichelectromagnetic signals are received.

In some examples, the present radio system transmits an electromagneticsignal to nearby devices requesting the device respond. The radio systemalso receives responses to the electromagnetic signal from the nearbydevices. Based on the radio technology used, the signaling of thetransmitted electromagnetic signal may be varied. For example, thetransmitted electromagnetic signal may be a Bluetooth, 802.11, or otherradio signal. A device that received the signal from the radio unit maytransmit a response signal with the same radio technology. However, insome instances, the radio technology used for communication may operateon several radio (e.g., frequency) channels. Both the transmitter andreceiver must operate on the same channel at the same time in order tocommunicate. Thus, it may be desirable to transmit the electromagneticsignal on more than one channel at the same time, in order to increasethe chances that a nearby device responds.

Some conventional radio systems, such as Bluetooth, establish acommunication by following a pattern of searching for devices to pair(e.g., synchronize) with on available radio channels. Conventionally, afirst device known as a master will send a request on a first channeland if it does not get a response from a slave device, the master devicewill increase the channel and repeat the process. A slave device willtypically listen on a first channel for a request, if it does not hearone, it may decrease the channel and repeat the process. Thus, at somepoint in time, both devices will be operating on the same channel andthe slave will transmit a response when it receives the request.However, there may be a period of time where both devices are withinrange of each other, but not operating on the same frequency. Thus, theycannot communicate with each other (and therefore cannot detect eachother) until both devices are operating on the same frequency channel.In other embodiments, the channels may be adjusted in a different way(e.g., the slave may increase channels and the master may decreasechannels, or any other method may be used).

In order to reduce the amount of time it takes to discover devices, theradio system of the autonomous vehicle may simultaneously transmit thesame electromagnetic signal on multiple channels, to request that nearbydevices respond. In one example, the radio technology may be Bluetooth,and Bluetooth may have 79 different channels. As such, the radio systemof the vehicle may send a request on all or a portion of the 79 radiochannels in order to request a response from any nearby device thatreceives the request. The radio system may therefore receive responsesfrom devices within the range of the radio signal. By transmitting therequest on more than one channel at a time, the amount of time needed tofind a wireless device associated with a pedestrian may be reduced. Insome embodiments, the radio system of the autonomous vehicle maytransmit the electromagnetic signal on multiple channels without waitingfor a response signal. In these embodiments, the radio signal may not betransmitted at exactly the same time, but the radio system is stilltransmitting on more than one channel without waiting for a responsesignal before transmitting on a second channel.

In some embodiments, the radio system may be configured with multipleantennas. By having multiple antennas, the radio system may have morecontrol over the radio signals. For example, the radio system may beable to adjust the beam-width and/or the direction of a transmittedsignal. Having more control over the radio signal allows the radiosystem to more accurately locate wireless devices (and the associatedpedestrian). In one embodiment, a plurality of antennas may be arrangedin an array. Such an array may be a linear array, a two-dimensionalarray, a three-dimensional array, a conformal array, or another arrayconfiguration.

Further, in some examples, the radio system on the car can also use anarray of whip antennas, giving the radio system more range than usualand may allow the processing layer to measure the direction of arrivalof the signal. In still other examples, different antenna technologiesmay be used to increase the range of detection and/or increase theability to locate pedestrians. Further, in some examples, the antennafor transmission may be different from the antenna used for reception ofradio signals.

Example systems within the scope of the present disclosure will now bedescribed in greater detail. An example system may be implemented in ormay take the form of an automobile. However, an example system may alsobe implemented in or take the form of other vehicles, such as cars,trucks, motorcycles, buses, boats, airplanes, helicopters, lawn mowers,earth movers, boats, snowmobiles, aircraft, recreational vehicles,amusement park vehicles, farm equipment, construction equipment, trams,golf carts, trains, and trolleys. Other vehicles are possible as well.

FIG. 1 is a functional block diagram illustrating a vehicle 100,according to an example embodiment. The vehicle 100 could be configuredto operate fully or partially in an autonomous mode. For example, acomputer system could control the vehicle 100 while in the autonomousmode, and may be operable to transmit a discovery radio signal, receiveresponse radio signals with at least one antenna in the radio system,analyze the response radio signal to determine if the radio signal isassociated with a pedestrian, and based on the received radio signalbeing associated with a pedestrian, altering the control of the vehicleby a control system based on the presence of the pedestrian. While inautonomous mode, the vehicle 100 may be configured to operate withouthuman interaction.

The vehicle 100 could include various subsystems such as a propulsionsystem 102, a sensor system 104, a control system 106, one or moreperipherals 108, as well as a power supply 110, a computer system 112, adata storage 114, and a user interface 116. The vehicle 100 may includemore or fewer subsystems and each subsystem could include multipleelements. Further, each of the subsystems and elements of vehicle 100could be interconnected. Thus, one or more of the described functions ofthe vehicle 100 may be divided up into additional functional or physicalcomponents, or combined into fewer functional or physical components. Insome further examples, additional functional and/or physical componentsmay be added to the examples illustrated by FIG. 1.

The propulsion system 102 may include components operable to providepowered motion for the vehicle 100. Depending upon the embodiment, thepropulsion system 102 could include an engine/motor 118, an energysource 119, a transmission 120, and wheels/tires 121. The engine/motor118 could be any combination of an internal combustion engine, anelectric motor, steam engine, Stirling engine. Other motors and/orengines are possible. In some embodiments, the engine/motor 118 may beconfigured to convert energy source 119 into mechanical energy. In someembodiments, the propulsion system 102 could include multiple types ofengines and/or motors. For instance, a gas-electric hybrid car couldinclude a gasoline engine and an electric motor. Other examples arepossible.

The energy source 119 could represent a source of energy that may, infull or in part, power the engine/motor 118. Examples of energy sources119 contemplated within the scope of the present disclosure includegasoline, diesel, other petroleum-based fuels, propane, other compressedgas-based fuels, ethanol, solar panels, batteries, and other sources ofelectrical power. The energy source(s) 119 could additionally oralternatively include any combination of fuel tanks, batteries,capacitors, and/or flywheels. The energy source 118 could also provideenergy for other systems of the vehicle 100.

The transmission 120 could include elements that are operable totransmit mechanical power from the engine/motor 118 to the wheels/tires121. The transmission 120 could include a gearbox, a clutch, adifferential, and a drive shaft. Other components of transmission 120are possible. The drive shafts could include one or more axles thatcould be coupled to the one or more wheels/tires 121.

The wheels/tires 121 of vehicle 100 could be configured in variousformats, including a unicycle, bicycle/motorcycle, tricycle, orcar/truck four-wheel format. Other wheel/tire geometries are possible,such as those including six or more wheels. Any combination of thewheels/tires 121 of vehicle 100 may be operable to rotate differentiallywith respect to other wheels/tires 121. The wheels/tires 121 couldrepresent at least one wheel that is fixedly attached to thetransmission 120 and at least one tire coupled to a rim of the wheelthat could make contact with the driving surface. The wheels/tires 121could include any combination of metal and rubber. Other materials arepossible.

The sensor system 104 may include several elements such as a GlobalPositioning System (GPS) 122, an inertial measurement unit (IMU) 124, aradar 126, a laser rangefinder/LIDAR 128, a camera 130, a steeringsensor 123, and a throttle/brake sensor 125. The sensor system 104 couldalso include other sensors, such as those that may monitor internalsystems of the vehicle 100 (e.g., O₂ monitor, fuel gauge, engine oiltemperature, brake wear).

The GPS 122 could include a transceiver operable to provide informationregarding the position of the vehicle 100 with respect to the Earth. TheIMU 124 could include a combination of accelerometers and gyroscopes andcould represent any number of systems that sense position andorientation changes of a body based on inertial acceleration.Additionally, the IMU 124 may be able to detect a pitch and yaw of thevehicle 100. The pitch and yaw may be detected while the vehicle isstationary or in motion.

The radar 126 may represent a system that utilizes radio signals tosense objects, and in some cases their speed and heading, within thelocal environment of the vehicle 100. Additionally, the radar 126 mayhave a plurality of antennas configured to transmit and receive radiosignals. The laser rangefinder/LIDAR 128 could include one or more lasersources, a laser scanner, and one or more detectors, among other systemcomponents. The laser rangefinder/LIDAR 128 could be configured tooperate in a coherent mode (e.g., using heterodyne detection) or in anincoherent detection mode. The camera 130 could include one or moredevices configured to capture a plurality of images of the environmentof the vehicle 100. The camera 130 could be a still camera or a videocamera.

The steering sensor 123 may represent a system that senses the steeringangle of the vehicle 100. In some embodiments, the steering sensor 123may measure the angle of the steering wheel itself. In otherembodiments, the steering sensor 123 may measure an electrical signalrepresentative of the angle of the steering wheel. Still, in furtherembodiments, the steering sensor 123 may measure an angle of the wheelsof the vehicle 100. For instance, an angle of the wheels with respect toa forward axis of the vehicle 100 could be sensed. Additionally, in yetfurther embodiments, the steering sensor 123 may measure a combination(or a subset) of the angle of the steering wheel, electrical signalrepresenting the angle of the steering wheel, and the angle of thewheels of vehicle 100.

The throttle/brake sensor 125 may represent a system that senses theposition of either the throttle position or brake position of thevehicle 100. In some embodiments, separate sensors may measure thethrottle position and brake position. In some embodiments, thethrottle/brake sensor 125 may measure the angle of both the gas pedal(throttle) and brake pedal. In other embodiments, the throttle/brakesensor 125 may measure an electrical signal that could represent, forinstance, an angle of a gas pedal (throttle) and/or an angle of a brakepedal. Still, in further embodiments, the throttle/brake sensor 125 maymeasure an angle of a throttle body of the vehicle 100. The throttlebody may include part of the physical mechanism that provides modulationof the energy source 119 to the engine/motor 118 (e.g., a butterflyvalve or carburetor). Additionally, the throttle/brake sensor 125 maymeasure a pressure of one or more brake pads on a rotor of vehicle 100.In yet further embodiments, the throttle/brake sensor 125 may measure acombination (or a subset) of the angle of the gas pedal (throttle) andbrake pedal, electrical signal representing the angle of the gas pedal(throttle) and brake pedal, the angle of the throttle body, and thepressure that at least one brake pad is applying to a rotor of vehicle100. In other embodiments, the throttle/brake sensor 125 could beconfigured to measure a pressure applied to a pedal of the vehicle, suchas a throttle or brake pedal.

The control system 106 could include various elements include steeringunit 132, throttle 134, brake unit 136, a sensor fusion algorithm 138, acomputer vision system 140, a navigation/pathing system 142, and anobstacle avoidance system 144. The steering unit 132 could represent anycombination of mechanisms that may be operable to adjust the heading ofvehicle 100. The throttle 134 could control, for instance, the operatingspeed of the engine/motor 118 and thus control the speed of the vehicle100. The brake unit 136 could be operable to decelerate the vehicle 100.The brake unit 136 could use friction to slow the wheels/tires 121. Inother embodiments, the brake unit 136 could convert the kinetic energyof the wheels/tires 121 to electric current.

A sensor fusion algorithm 138 could include, for instance, a Kalmanfilter, Bayesian network, or other algorithm that may accept data fromsensor system 104 as input. The sensor fusion algorithm 138 couldprovide various assessments based on the sensor data. Depending upon theembodiment, the assessments could include evaluations of individualobjects and/or features, evaluation of a particular situation, and/orevaluate possible impacts based on the particular situation. Otherassessments are possible.

The computer vision system 140 could include hardware and softwareoperable to process and analyze images in an effort to determineobjects, important environmental features (e.g., stop lights, road wayboundaries, etc.), and obstacles. The computer vision system 140 coulduse object recognition, Structure From Motion (SFM), video tracking, andother algorithms used in computer vision, for instance, to recognizeobjects, map an environment, track objects, estimate the speed ofobjects, etc.

The navigation/pathing system 142 could be configured to determine adriving path for the vehicle 100. The navigation/pathing system 142 mayadditionally update the driving path dynamically while the vehicle 100is in operation. In some embodiments, the navigation/pathing system 142could incorporate data from the sensor fusion algorithm 138, the GPS122, and known maps so as to determine the driving path for vehicle 100.

The obstacle avoidance system 144 could represent a control systemconfigured to evaluate potential obstacles based on sensor data andcontrol the vehicle 100 to avoid or otherwise negotiate the potentialobstacles.

Various peripherals 108 could be included in vehicle 100. For example,peripherals 108 could include a wireless communication system 146, atouchscreen 148, a microphone 150, and/or a speaker 152. The peripherals108 could provide, for instance, means for a user of the vehicle 100 tointeract with the user interface 116. For example, the touchscreen 148could provide information to a user of vehicle 100. The user interface116 could also be operable to accept input from the user via thetouchscreen 148. In other instances, the peripherals 108 may providemeans for the vehicle 100 to communicate with devices within itsenvironment.

In one example, the wireless communication system 146 could beconfigured to wirelessly communicate with one or more devices directlyor via a communication network. For example, wireless communicationsystem 146 could use 3G cellular communication, such as CDMA, EVDO,GSM/GPRS, or 4G cellular communication, such as WiMAX or LTE.Alternatively, wireless communication system 146 could communicate witha wireless local area network (WLAN), for example, using WiFi. In someembodiments, wireless communication system 146 could communicatedirectly with a device, for example, using an infrared link, Bluetooth,or ZigBee. Other wireless protocols, such as various vehicularcommunication systems, are possible within the context of thedisclosure. For example, the wireless communication system 146 couldinclude one or more dedicated short range communications (DSRC) devicesthat could include public and/or private data communications betweenvehicles and/or roadside stations.

The power supply 110 may provide power to various components of vehicle100 and could represent, for example, a rechargeable lithium-ion orlead-acid battery. In an example embodiment, one or more banks of suchbatteries could be configured to provide electrical power. Other powersupply materials and types are possible. Depending upon the embodiment,the power supply 110, and energy source 119 could be integrated into asingle energy source, such as in some all-electric cars.

Many or all of the functions of vehicle 100 could be controlled bycomputer system 112. Computer system 112 may include at least oneprocessor 113 (which could include at least one microprocessor) thatexecutes instructions 115 stored in a non-transitory computer readablemedium, such as the data storage 114. The computer system 112 may alsorepresent a plurality of computing devices that may serve to controlindividual components or subsystems of the vehicle 100 in a distributedfashion.

In some embodiments, data storage 114 may contain instructions 115(e.g., program logic) executable by the processor 113 to execute variousfunctions of vehicle 100, including those described above in connectionwith FIG. 1. Data storage 114 may contain additional instructions aswell, including instructions to transmit data to, receive data from,interact with, and/or control one or more of the propulsion system 102,the sensor system 104, the control system 106, and the peripherals 108.

In addition to the instructions 115, the data storage 114 may store datasuch as roadway maps, path information, among other information. Suchinformation may be used by vehicle 100 and computer system 112 duringthe operation of the vehicle 100 in the autonomous, semi-autonomous,and/or manual modes.

The vehicle 100 may include a user interface 116 for providinginformation to or receiving input from a user of vehicle 100. The userinterface 116 could control or enable control of content and/or thelayout of interactive images that could be displayed on the touchscreen148. Further, the user interface 116 could include one or moreinput/output devices within the set of peripherals 108, such as thewireless communication system 146, the touchscreen 148, the microphone150, and the speaker 152.

The computer system 112 may control the function of the vehicle 100based on inputs received from various subsystems (e.g., propulsionsystem 102, sensor system 104, and control system 106), as well as fromthe user interface 116. For example, the computer system 112 may utilizeinput from the sensor system 104 in order to estimate the outputproduced by the propulsion system 102 and the control system 106.Depending upon the embodiment, the computer system 112 could be operableto monitor many aspects of the vehicle 100 and its subsystems. In someembodiments, the computer system 112 may disable some or all functionsof the vehicle 100 based on signals received from sensor system 104.

The components of vehicle 100 could be configured to work in aninterconnected fashion with other components within or outside theirrespective systems. For instance, in an example embodiment, the camera130 could capture a plurality of images that could represent informationabout a state of an environment of the vehicle 100 operating in anautonomous mode. The state of the environment could include parametersof the road on which the vehicle is operating. For example, the computervision system 140 may be able to recognize the slope (grade) or otherfeatures based on the plurality of images of a roadway. Additionally,the combination of Global Positioning System 122 and the featuresrecognized by the computer vision system 140 may be used with map datastored in the data storage 114 to determine specific road parameters.Further, the radar unit 126 may also provide information about thesurroundings of the vehicle.

In other words, a combination of various sensors (which could be termedinput-indication and output-indication sensors) and the computer system112 could interact to provide an indication of an input provided tocontrol a vehicle or an indication of the surroundings of a vehicle.

The computer system 112 could carry out several determinations based onthe signals received by the sensor system 104 (e.g., the radio unit).For example, the computer system 112 could calculate the direction (e.g.angle) and distance (e.g. range) to one or more devices transmitting aresponse signal. The distance may correspond to a time delay and/or apower level of the received radio signal. Additionally, the radio systemmay be configured to determine whether each device transmitting aresponse signal is a pedestrian or not. Based on the determination ofpedestrian or not, the processor may adjust the control system of theautonomous vehicle.

In some embodiments, the computer system 112 may make a determinationabout various objects based on data that is provided by systems otherthan the radio system. For example, the vehicle may have lasers or otheroptical sensors configured to sense objects in a field of view of thevehicle. The computer system 112 may use the outputs from the varioussensors to determine information about objects in a field of view of thevehicle. The computer system 112 may determine distance and directioninformation to the various objects. The computer system 112 may alsodetermine whether objects are desirable or undesirable based on theoutputs from the various sensors.

Although FIG. 1 shows various components of vehicle 100, i.e., wirelesscommunication system 146, computer system 112, data storage 114, anduser interface 116, as being integrated into the vehicle 100, one ormore of these components could be mounted or associated separately fromthe vehicle 100. For example, data storage 114 could, in part or infull, exist separate from the vehicle 100. Thus, the vehicle 100 couldbe provided in the form of device elements that may be locatedseparately or together. The device elements that make up vehicle 100could be communicatively coupled together in a wired and/or wirelessfashion.

FIG. 2 shows a vehicle 200 that could be similar or identical to vehicle100 described in reference to FIG. 1. Depending on the embodiment,vehicle 200 could include a sensor unit 202, a wireless communicationsystem 204, a radio unit 206, a laser rangefinder 208, and a camera 210.The elements of vehicle 200 could include some or all of the elementsdescribed for FIG. 1. Although vehicle 200 is illustrated in FIG. 2 as acar, other embodiments are possible. For instance, the vehicle 200 couldrepresent a truck, a van, a semi-trailer truck, a motorcycle, a golfcart, an off-road vehicle, or a farm vehicle, among other examples.

The sensor unit 202 could include one or more different sensorsconfigured to capture information about an environment of the vehicle200. For example, sensor unit 202 could include any combination ofcameras, radars, LIDARs, range finders, radio devices (e.g., Bluetoothand/or 802.11), and acoustic sensors. Other types of sensors arepossible. Depending on the embodiment, the sensor unit 202 could includeone or more movable mounts that could be operable to adjust theorientation of one or more sensors in the sensor unit 202. In oneembodiment, the movable mount could include a rotating platform thatcould scan sensors so as to obtain information from each directionaround the vehicle 200. In another embodiment, the movable mount of thesensor unit 202 could be moveable in a scanning fashion within aparticular range of angles and/or azimuths. The sensor unit 202 could bemounted atop the roof of a car, for instance, however other mountinglocations are possible. Additionally, the sensors of sensor unit 202could be distributed in different locations and need not be collocatedin a single location. Some possible sensor types and mounting locationsinclude radio unit 206 and laser range finder 208.

The wireless communication system 204 could be located as depicted inFIG. 2. Alternatively, the wireless communication system 204 could belocated, fully or in part, elsewhere. The wireless communication system204 may include wireless transmitters and receivers that could beconfigured to communicate with devices external or internal to thevehicle 200. Specifically, the wireless communication system 204 couldinclude transceivers configured to communicate with other vehiclesand/or computing devices, for instance, in a vehicular communicationsystem or a roadway station. Examples of such vehicular communicationsystems include dedicated short range communications (DSRC), radiofrequency identification (RFID), and other proposed communicationstandards directed towards intelligent transport systems.

The camera 210 could be mounted inside a front windshield of the vehicle200. The camera 210 could be configured to capture a plurality of imagesof the environment of the vehicle 200. Specifically, as illustrated, thecamera 210 could capture images from a forward-looking view with respectto the vehicle 200. Other mounting locations and viewing angles ofcamera 210 are possible. The camera 210 could represent one or morevisible light cameras. Alternatively or additionally, camera 210 couldinclude infrared sensing capabilities. The camera 210 could haveassociated optics that could be operable to provide an adjustable fieldof view. Further, the camera 210 could be mounted to vehicle 200 with amovable mount that could be operable to vary a pointing angle of thecamera 210.

A method 300 is provided for operating a radio system of an autonomousvehicle to aid in the discovery and identification of pedestrians. Themethod could be performed using any of the apparatus shown in FIGS. 1-2and FIGS. 4-5 and described herein; however, other configurations couldbe used as well. FIG. 3 illustrates the blocks in an example method.However, it is understood that in other embodiments, the blocks mayappear in different order and blocks could be added, subtracted, ormodified. Additionally, the blocks may be performed in a linear manner(as shown) or may be performed in a parallel manner (not shown).

Block 302 includes the vehicle transmitting a first electromagneticradiation signal from a radio unit. The electromagnetic signal may takethe form of a Bluetooth signal, 802.11 signal, and/or other radiotechnology signal. The vehicle described in this method could be thevehicle 100 and/or vehicle 200 as illustrated and described in referenceto FIGS. 1 and 2, respectively. The first electromagnetic radiationsignal may be transmitted via one or more antennas located in a radiounit. Further, the first electromagnetic radiation signal may betransmitted with one of many different radio-signaling modes. However,in some embodiments it is desirable to transmit the firstelectromagnetic radiation signal with a signaling mode that requests aresponse from devices located near the autonomous vehicle.

For example, at block 302, the vehicle may transmit a signal based on aradio technology such as Bluetooth or 802.11. As previously discussed,in some instances, the radio technology used for communication mayoperate on several radio (e.g., frequency) channels. Both thetransmitter (e.g., the vehicle's radio unit) and receiver (e.g., amobile device) must operate on the same channel at the same time inorder to communicate. Thus, at block 302 it may be desirable for thevehicle's radio unit to transmit the electromagnetic signal on more thanone channel at the same time, in order to increase the chances that anearby device responds.

A traditional Bluetooth radio establishes a communication link byfollowing a pattern of searching for devices to pair (e.g., synchronize)with on available radio channels. Conventionally, a first device knownas a master (here, the vehicle) will send a request on a first channeland if it does not get a response from a slave device (here, a mobiledevice), increase the channel and repeat the process. The slave devicewill typically listen on a first channel for a request, if it does nothear one, it may decrease the channel and repeat the process. Thus, atsome point in time, both devices will be operating on the same channeland the slave will transmit a response when it receives the request.However, there may be a period of time where both devices are withinrange of each other, but not operating on the same frequency. Thus, theycannot communicate with each other (and therefore cannot detect eachother) until both devices are operating on the same frequency channel.

In order to reduce the amount of time it takes to discover devices, atBlock 302 the radio system of the autonomous vehicle may use an improvedmethod of searching for devices near the radio unit of the vehicle. Theradio system of the vehicle may simultaneously transmit anelectromagnetic signal to nearby devices requesting the device respondon more than one channel associated with the radio technology.

In one example, the radio technology may be Bluetooth having 79different channels. The radio system of the vehicle may send a requeston all or a portion of the 79 radio channels requesting the devicerespond. The radio system may receive responses from devices within therange of the radio signal. By transmitting the request to have devicesrespond on more than one channel at a time, the about of time needed tofind a wireless device associated with a pedestrian may be reduced.

In some embodiments, the radio system of the autonomous vehicle maytransmit the electromagnetic signal on multiple channels without waitingfor a response signal. In these embodiments, the radio signal may not betransmitted at exactly the same time, but the radio system is stilltransmitting on more than one channel without waiting for a responsesignal before transmitting on a second channel. Each transmission may betransmitted a slightly different time than transmissions on otherchannels (e.g., transmissions are performed at the same time), althoughthey may not be synchronized to all occur at the same instant.

In some embodiments, the radio system of the vehicle may be configuredwith multiple antennas. By having multiple antennas, the radio systemmay have more control over the radio signals. In some embodiments, eachantenna may be arranged in a specific direction and each antennaprimarily sends and receives signals in the specific direction. In otherembodiments, the antennas may form an array. When formed in an array,the radio system may be able to adjust the beam-width and/or directionof a transmitted signal. The beam-width may be narrowed to increase thetransmission range or in may be widened to provide a wider transmissionwidth. The antenna beam-widths are discussed further with respect to thevarious scenarios shown in FIGS. 4A-4C. For example, FIG. 4A shows theantenna system having a first beam-width and FIG. 4C shows the antennasystem having a second wider beam-width. Additionally, the array may bea linear array, a two dimensional array, three dimensional array,conformal array, or other array configuration.

Further, in some examples, the radio system on the car can also use anarray of whip antennas, giving the radio system more range than if theradio system used typical antennas. In still other examples, differentantenna technologies may be used to increase the range of detectionand/or increase the ability to locate pedestrians. In some examples, theantenna for transmission may be different from the antenna used forreception of radio signals.

Block 304 includes the vehicle receive response radio signals at a radiounit of the autonomous vehicle with the radio unit. Receiving theresponse electromagnetic radiation signal could include receiving radiosignals that are communicated from mobile devices located onpedestrians. Devices that receive the signal may responsively send acommunication back to the vehicle.

Additionally, the type and positioning of the antennas in the radio unitof vehicle may aid in the detection of pedestrians. Having the antennasformed in an array may allow the vehicle to use digital signalprocessing to perform direction of arrival analysis of the receivedsignals. An array formation may also allow the radio unit to adjust thebeam-width and/or direction to focus to look for a signal to receive.The beam-width may be narrowed to increase the detection range or in maybe widened to provide a wider detection range. However, there may alsobe embodiments where the antennas do not form an array. In theseembodiments, antennas may be selected based on directionality,polarization, or other criteria. In one example, FIG. 4A shows theantenna system having a first beam-width and FIG. 4C shows the antennasystem having a second wider beam-width. The beam width may be adjustedfrom that of FIG. 4A to that of FIG. 4C based on the location ofpedestrians, such as that shown in FIG. 4B.

Block 306 includes the vehicle analyzing the response radio signal todetermine if the radio signal is associated with a pedestrian. Aprocessor in the vehicle may be configured to calculate some parametersof objects that transmit a response signal back to the radio system. Forexample, in one embodiment, the processor is configured to calculate thedistance and/or angle to various objects that transmit a response signalback to the radio system. The distance may correspond to a time delayand/or a power level of the received radio signal. Additionally, theradio system may be configured to determine whether each devicetransmitting a response signal is a pedestrian or not.

Further, the vehicle may make the determination of whether the receivedsignal is associated with a pedestrian based on a variety of criteria.First, in some examples, the mobile device may communicate dataidentifying the mobile device. For example, the data may include aBluetooth identification of the model of the mobile device. Further, amobile device such as a phone, which is typically on a person, may beindicative of a pedestrian.

The device may also send some information about itself along with itsresponse. For example, in some embodiments the device may identifyitself as a cellular phone. Therefore, the vehicle may be able toidentify the type of device that is sending a response. This may enableto vehicle to determine if a pedestrian may carry the device. In anotherexample, if the response includes data indicating that it is a car(e.g., the Bluetooth identifier is associated with a car manufacturer),then the vehicle can determine is it not associated with a pedestrian.

In another example, the vehicle may use other sensors, in combinationwith the radio unit, to identify pedestrians. For example, an opticalsensor, such as a video camera may be able to image the area around thevehicle. The optical sensor may also be able to identify pedestrianslocated near the vehicle. However, in some situations the optical sensormay not have a high confidence that it has identified a pedestrian. Thevehicle may combine information from the optical sensors and a receivedsignal from the radio unit to confirm that an identified object is apedestrian. The radio unit may receive a signal indicating that there isone pedestrian directly in front of the vehicle. The optical sensor mayidentify a single object in front of the vehicle, but it may not be ableto determine what the object is. A processing unit in the vehicle may beable to determine that the object is pedestrian through using theinformation from the received radio signal.

The vehicle may also use stored map information to determine if thereceived signal is from a mobile device associated with a pedestrian.The vehicle may be able to determine that the mobile device would beassociated with a pedestrian, as a mobile device, such a cellular phone,typically would not be present near a roadway except when located on apedestrian. Additionally, if an angle and distance to a device areknown, the vehicle may be able to compare these parameters to known mapinformation. By comparing the parameters to the stored map information,the vehicle may be able to determine if it is possible for a pedestrianto be located in the position indicated by the angle and distance.Further, the angle and distance may also be used with Block 308, when acontrol of the vehicle is adjusted.

In some embodiments, the mobile device may be configured to communicatemotion information along with the response signal. In this embodiment,the vehicle may transmit a signal to request motion data from responsivedevices. The mobile device may include information measured by aninertial measurement unit (IMU) of the mobile device. For example, anIMU of a mobile may contain an accelerometer and/or a gyroscope thatenable the mobile to accurately measure its movement. The movement maybe measured in terms of a position, velocity, etc. In other embodiments,the mobile may be able to measure movement information without the useof an IMU (e.g., movement information may come from a cellular-locationservice). The mobile may communicate some or all of the movementinformation from the IMU to the vehicle. The vehicle may use themovement information to determine if the mobile is associated with apedestrian.

Block 308 includes based on the received radio signal being associatedwith a pedestrian, altering the control of the vehicle by a controlsystem based on the presence of the pedestrian. The autonomous vehicleis configured to control some or all of the driving aspects of vehicleoperation with a vehicle control system. When operating autonomously, atleast one computing device located onboard and/or in a server networkcould be operable to carry out functions such as planning a drivingroute, sensing aspects of the vehicle, sensing the environment of thevehicle, and controlling drive components such as steering, throttle,and brake. Altering the control of the vehicle may include performing amodified driving behavior.

When the vehicle determines that a pedestrian is located near thevehicle, it may adjust the control of the vehicle based on the presenceof the pedestrian. In an example, a computing device may be configuredto control actuators of the first vehicle using an action set or ruleset associated with the modified control strategy. For instance, thecomputing device may be configured to adjust translational velocity, orrotational velocity, or both, of the vehicle based on the modifieddriving behavior. In additional examples, the computing device may altera course of the vehicle or alter a speed of the vehicle. The computingdevice may calculate vehicle control signals based on the detectedpedestrians.

Example methods, such as method 300 of FIG. 3, may be carried out inwhole or in part by the vehicle and its subsystems. Accordingly, examplemethods could be described by way of example herein as being implementedby the vehicle. However, it should be understood that an example methodmay be implemented in whole or in part by other computing devices. Forexample, an example method may be implemented in whole or in part by aserver system, which receives data from a device such as thoseassociated with the vehicle. Other examples of computing devices orcombinations of computing devices that can implement an example methodare possible.

In some additional embodiments mobile devices may be configured with asafety or protection mode. In this mode, the mobile may eithercontinuously or intermittently attempt to communicate signals to nearbydevices indicating the presence of a pedestrian. For example, a personmay bike or run while in possession of his or her mobile phone. When thesafety or protection mode is enabled, the mobile will attempt toindicate the presence of the pedestrian to various device located nearthe pedestrian. The safety or protection mode may operate on a mobiledevice in conjunction with a method, such as method 300, operating on anautonomous vehicle.

FIG. 4A illustrates a scenario 400 involving a vehicle 402 travelingdown a roadway 404. Vehicle 402 could be operating in an autonomousmode. Further, the vehicle 402 may be configured with a sensor unit 410.In one example, the sensor unit 410 may have four associated beam-widths406A-406D. Each beam-width may correspond to an antenna located in thesensor unit 410. Additionally, the each beam-width may correspond to aregion over which the respective antenna can transmit and/or receiveradio signals. In other examples, the beam-width may be based on anarray of antennas within the sensor unit 410. Further, the beam-width(s)may have different shapes or regions than those shown in FIG. 3A. FIG.3A is one example of possible beam-widths for the sensor unit 410. Instill further embodiments, the vehicle 302 may have more than fourbeam-widths.

In one example embodiment, there may be two pedestrians 412 and 414 infront of the vehicle 402, each of who are carrying a mobile devicehaving a wireless technology. A first pedestrian 412 and a secondpedestrian 414 may be within the beam-widths 406C and 406A of the sensorunit 410, respectively. As shown in FIG. 3A, pedestrians 412 and 414 maybe crossing in a crosswalk in front of vehicle 402. As shown in FIG. 3A,both pedestrians 412 and 414 are carrying a mobile device having awireless technology. The autonomous vehicle may recognize the presenceof the pedestrians based on signals communicated by the mobile devicepossessed by each pedestrian.

Because a pedestrian 412 is primarily within the beam-width 406C, thevehicle 402 may be able to determine that a pedestrian 412 is located tothe side of the vehicle 402. Additionally, because a pedestrian 414 isprimarily within the beam-width 406A, the vehicle 402 may be able todetermine that a pedestrian 414 is located in the front of the vehicle402.

As shown in FIG. 3B, the two pedestrians 412 and 414 are no longerlocated in front of the vehicle 402. Because the two pedestrians 412 and414 are primarily within the beam-width 406C, the vehicle 402 may beable to determine that the two pedestrians 412 and 414 are located in tothe side of the vehicle 402.

In some embodiments, the vehicle 402 may be able to adjust beam-widths406A-406D like what is shown in FIG. 3C. As compared to FIG. 3B, thevehicle may be able to more precisely locate pedestrian 414 whenadjusting the beam-width. As the beam-width is adjusted, the pedestrian414 goes from being located within beam-width 406C to being locatedwithin beam-width 406A. Therefore, the vehicle will be able to interpretthe location of pedestrian 414 as being near where the adjustedbeam-width 406A is located.

In some embodiments, the beam-widths 406A-406D may be adjusted in a waythat the various beam-widths 406A-406D overlap with each other (notshown). For example, if beam-width 406A and beam-width 406D had anoverlap, receivers associated with both beam-widths may receive a signalcommunicated by a mobile device held by pedestrian within the overlapregion. Thus, the location of the mobile devices, and therefore thepedestrian, would likely be within the overlap region. Further, thesensor unit 410 may be able to steer (and/or widen or narrow) the radiobeam-widths so the beam-width 406 to more precisely locate mobiledevices located on pedestrians.

Additionally, because the vehicle 402 received signals from mobiledevices, for each mobile device that the vehicle 402 receives a signal,a computer located within vehicle 402 may determine if each receivedsignal is from a mobile device (and thus, a pedestrian). Further, thevehicle 402 may make the determination of whether the received signal isassociated with a pedestrian based on a variety of criteria. First, insome examples, the mobile device may intentionally communicate dataidentifying the mobile device. For example, the data may include aBluetooth identification of the model of the mobile device. The vehiclemay be able to determine that the mobile device would be associated witha pedestrian, as a mobile device, such a cellular phone, typically wouldnot be present near a roadway except when located on a pedestrian. Inanother example, the vehicle 402 may use other sensors, in combinationwith the radio unit, to identify pedestrians. For example, an opticalsensor, such as a video camera may be able to image the area around thevehicle 402. The optical sensor may also be able to identify pedestrianslocated near the vehicle 402. However, in some situations the opticalsensor may not have a high confidence that it has identified apedestrian. The vehicle 402 may combine information from the opticalsensors and a received signal from the radio unit to confirm that anidentified object is a pedestrian. The radio unit may receive a signalindicating that there is one pedestrian directly in front of the vehicle402. The optical sensor may identify a single object in front of thevehicle 402, but it may not be able to determine what the object is. Aprocessing unit in the vehicle 402 may be able to determine that theobject is pedestrian through using the information from the receivedradio signal.

It will be understood that there are other similar methods that coulddescribe receiving data representative of an electromagnetic signal,receiving an indication of a movement of the vehicle, determining amovement parameter based the indication of the movement of the vehicle,and recovering the distance and direction information from theelectromagnetic signal, based on the movement parameter. Those similarmethods are implicitly contemplated herein.

In some embodiments, the disclosed methods may be implemented ascomputer program instructions encoded on a non-transitorycomputer-readable storage media in a machine-readable format, or onother non-transitory media or articles of manufacture. FIG. 5 is aschematic illustrating a conceptual partial view of an example computerprogram product that includes a computer program for executing acomputer process on a computing device, arranged according to at leastsome embodiments presented herein.

In one embodiment, the example computer program product 500 is providedusing a signal bearing medium 502. The signal bearing medium 502 mayinclude one or more programming instructions 504 that, when executed byone or more processors may provide functionality or portions of thefunctionality described above with respect to FIGS. 1-4. In someexamples, the signal bearing medium 502 may encompass a non-transitorycomputer-readable medium 506, such as, but not limited to, a hard diskdrive, a Compact Disc (CD), a Digital Video Disk (DVD), a digital tape,memory, etc. In some implementations, the signal bearing medium 502 mayencompass a computer recordable medium 508, such as, but not limited to,memory, read/write (R/W) CDs, R/W DVDs, etc. In some implementations,the signal bearing medium 502 may encompass a communications medium 510,such as, but not limited to, a digital and/or an analog communicationmedium (e.g., a fiber optic cable, a waveguide, a wired communicationslink, a wireless communication link, etc.). Thus, for example, thesignal bearing medium 502 may be conveyed by a wireless form of thecommunications medium 510.

The one or more programming instructions 504 may be, for example,computer executable and/or logic implemented instructions. In someexamples, a computing device such as the computer system 112 of FIG. 1may be configured to provide various operations, functions, or actionsin response to the programming instructions 504 conveyed to the computersystem 112 by one or more of the computer readable medium 506, thecomputer recordable medium 508, and/or the communications medium 510.

The non-transitory computer readable medium could also be distributedamong multiple data storage elements, which could be remotely locatedfrom each other. The computing device that executes some or all of thestored instructions could be a vehicle, such as the vehicle 200illustrated in FIG. 2. Alternatively, the computing device that executessome or all of the stored instructions could be another computingdevice, such as a server.

The above detailed description describes various features and functionsof the disclosed systems, devices, and methods with reference to theaccompanying figures. While various aspects and embodiments have beendisclosed herein, other aspects and embodiments will be apparent. Thevarious aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims.

What is claimed is:
 1. A method comprising: transmitting, by a firstcomputing device coupled to a vehicle, a device-discovery radio signalin an environment of the vehicle using a radio technology; receiving, atthe first computing device, a responsive radio signal from a secondcomputing device situated externally to the vehicle; based on theresponsive radio signal, determining that the second computing device isa pedestrian device; and controlling the vehicle based on determiningthat the second computing device is the pedestrian device.
 2. The methodof claim 1, wherein transmitting the device-discovery radio signal inthe environment of the vehicle using the radio technology comprises:transmitting a plurality of device-discovery radio signals on aplurality of channels.
 3. The method of claim 2, wherein transmittingthe plurality of device-discovery radio signals on the plurality ofchannels comprises: transmitting a first device-discovery radio signalon a first channel; and transmitting a second device-discovery radiosignal on a second channel without waiting for a response signal aftertransmitting the first device-discovery radio signal.
 4. The method ofclaim 1, further comprising: based on receiving the responsive radiosignal from the second computing device, determining a distance betweenthe vehicle and the second computing device and a direction of thesecond computing device relative to the vehicle.
 5. The method of claim4, wherein controlling the vehicle based on determining that the secondcomputing device is the pedestrian device comprises: adjusting atrajectory of the vehicle and a speed of the vehicle based on thedistance between the vehicle and the second computing device and thedirection of the second computing device relative to the vehicle.
 6. Themethod of claim 1, further comprising: responsive to receiving theresponsive radio signal from the second computing device situatedexternally to the vehicle, determining whether the second computingdevice is the pedestrian device or another type of device usinginformation in the responsive radio signal received from the secondcomputing device.
 7. The method of claim 6, wherein determining whetherthe second computing device is the pedestrian device or another type ofdevice comprises: determining that the second computing device isroadside station; and adjusting control of the vehicle based oncommunicating with the roadside station.
 8. The method of claim 6,wherein determining whether the second computing device is thepedestrian device or another type of device comprises: determining thatthe second computing device is a given vehicle in the environment of thevehicle; and controlling the vehicle based on determining that thesecond computing device is the given vehicle.
 9. The method of claim 1,wherein transmitting the device-discovery radio signal in theenvironment of the vehicle using the radio technology comprises:transmitting the device-discovery radio signal is transmitted on allfrequency channels of the radio technology using a sensor unit having aplurality of antennas, wherein each antenna is configured to send andreceive signals in a specific direction.
 10. The method of claim 1,wherein determining that the second computing device is the pedestriandevice comprises: receiving sensor data from a vehicle sensor; anddetermining that the second computing device is the pedestrian devicebased on the responsive radio signal and the sensor data.
 11. The methodof claim 1, further comprising: based on receiving the responsive radiosignal from the second computing device, transmitting a request formotion data to the second computing device; and receiving motion datafrom the second computing device.
 12. The method of claim 11, whereindetermining that the second computing device is the pedestrian devicecomprises: determining that the second computing device is thepedestrian device based on the motion data; and wherein controlling thevehicle based on determining that the second computing device is thepedestrian device further comprises: adjusting a trajectory of thevehicle further based on the motion data.
 13. The method of claim 1,wherein receiving the responsive radio signal from the second computingdevice situated externally to the vehicle comprises: receiving a firstresponsive radio signal from the second computing device and a secondresponsive radio signal from a third computing device; and whereindetermining that the second computing device is the pedestrian devicecomprises: determining that the second computing device is a firstpedestrian device based on the first responsive radio signal; anddetermining that the third computing device is a second pedestriandevice based on the second responsive radio signal.
 14. The method ofclaim 13, further comprising: determining a first location of the firstpedestrian device and a second location of the second pedestrian device;and wherein controlling the vehicle comprises: adjusting a trajectoryand a speed of the vehicle based on the first location of the firstpedestrian device and the second location of the second pedestriandevice.
 15. A system comprising: a sensor coupled to a vehicle; a firstcomputing device coupled to the vehicle, wherein the first computingdevice is configured to: transmit, using the sensor, a device-discoveryradio signal in an environment of the vehicle using a radio technology;receive a responsive radio signal from a second computing devicesituated externally to the vehicle; based on the responsive radiosignal, determine that the second computing device is a pedestriandevice; and control the vehicle based on determining that the secondcomputing device is the pedestrian device.
 16. The system of claim 15,wherein the first computing device is further configured to: based onreceiving the responsive radio signal from the second computing device,transmit a request for motion data to the second computing device; andreceive motion data from the second computing device.
 17. The system ofclaim 16, wherein the first computing device is further configured to:adjust a trajectory of the vehicle further based on the motion data. 18.The system of claim 15, wherein the first computing device is furtherconfigured to: transmit a first device-discovery radio signal on a firstchannel; and transmit a second device-discovery radio signal on a secondchannel without waiting for a response signal in response to the firstdevice-discovery radio signal.
 19. The system of claim 15, wherein thefirst computing device is further configured to: determine whether thesecond computing device is the pedestrian device or another type ofdevice using information in the responsive radio signal received fromthe second computing device; determine that the second computing deviceis roadside station; and adjusting control of the vehicle based oncommunication with the roadside station.
 20. An article of manufactureincluding a non-transitory computer-readable medium having storedthereon program instructions that, if executed by a processor, cause afirst computing device to perform operations comprising: transmitting adevice-discovery radio signal in an environment of a vehicle using aradio technology; receiving a responsive radio signal from a secondcomputing device situated externally to the vehicle; based on theresponsive radio signal, determining that the second computing device isa pedestrian device; and controlling the vehicle based on determiningthat the second computing device is the pedestrian device.